CompactionStats to support larger value of RecordIn and RecordDrop

Summary: now we use %8d for RecordIn and %10d for RecordDrop, which is far too small for some use cases. Extend both of them to %12d.

Test Plan: run one test in db_test and see the LOG file.

Reviewers: igor, MarkCallaghan, ljin

Reviewed By: ljin

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D28041

db/internal_stats.cc

@@ -66,8 +66,8 @@ void PrintLevelStats(char* buf, size_t len, const std::string& name,
     "%10.2f " /* Stall(sec) */
     "%10" PRIu64 " " /* Stall(cnt) */
     "%7.2f " /* Avg(ms) */
-    "%8d " /* input entries */
-    "%10d\n" /* number of records reduced */,
+    "%12d " /* input entries */
+    "%12d\n" /* number of records reduced */,
     name.c_str(), num_files, being_compacted, total_file_size / kMB, score,
     bytes_read / kGB,
     stats.bytes_readn / kGB,